Improvement in folding blackboards



B.GLLUTHER. Folding-Blapk-li-oard'.

No. 210,044. Pat nted Nov. 19, I878 WITNESSES. INVENTOR- UNITED STATES PATENT OFFICE.

BENJAMIN G. LUTHER, OF HEBRONVILLE, MASS, ASSIGNOR OF ONE-HALF HIS RIGHT TO JOHN W. TILLINGHAST, OF PROVIDENCE, It. I.

IMPROVEMENT 'IN FOLDING BLACKBOARDS.'

Specification forming part of Letters Patent No. 210,044, dated November I9, 1878; application filed October 17, 1878.

To all whom it may concern:

Be it known that I, BENJAMIN G. LUTHER,

' of Hebronville, in Bristol county, Massachusetts, have invented an Improvement in Folding Blackboards, of which the following is a specification The nature of my invention consists in a flexible fabric treated with any of the ordinary compositions, whereby a flexible surface may be produced suitable for the use of a blackboard or slate, to which grooved top and bottom pieces are so secured that the insertion of either pivoted or separate stretchers may serve to properly extend and hold the fabric for use as an ordinary blackboard.

Figure l is a back view of the board, showing the top and bottompieces andthe stretchers. Fig. 2 is a vertical section. I

In the drawing, A is the flexible fabric, covered on both sides with a suitable preparation, as usual in the manufacture of flexible slates. Upon the upper and lower edges of the fabric A are secured the clamp-pieces B B, so constructed and arranged as to form a groove, 0, to be terminated at each end by the fixed pieces D D.

The stretchers may beeit-her pivoted at one end to the clamp-piece B, as shown by the stretcher E, or may be formed of two similar loose pieces, as shown by E. I prefer to pivot one of the stretchers in the groove of one of the pieces B, and to pivot the other stretcher in the groove of the opposite piece B, so that each stretcher may fold down into the groove of the clamp-piece to which it is attached, when the whole may be rolled up for convenient transportation or other desired purpose. In stretching the flexible blackboard the free ends of the pivoted stretchers are entered into the groove 0 of the opposite clamp-pieces, respectively, and then forced toward the end pieces, D D, by which means the fabric will be drawn as tight as desired. 'If the stretchers are loose instead of being pivoted, they are placed with one end against the end pieces, D D, and then operated as above described for the pivoted stretchers When one side of the improved folding blackboard has been covered with figures, the opposite side may be utilized in a similar manner by removing the stretchers and turning over the clamp-pieces B B, by which means the groove 0 will be brought upon the opposite side of the board, when thestretchers may be inserted as before.

The drawing shows the fabric A as being firmly held at the points a a, so that the whole will present the same appearance when reversed; but the fabric may be otherwise attached, if it is only desired for folding.

I claim as my inv ention 1. The prepared fabric A and grooved strips B B, in combination with the stretchers E or E, inserted into the grooves G, and operated substantially as described.

2. The reversible strips B B, combined with the prepared flexible fabric A, substantially as described.

BENJAMIN G. LUTHER.

Witnesses SOCRATES SCHOLFIELD, Ln GRAND SoHoLFIELD. 

